UPSD3254 STMICROELECTRONICS [STMicroelectronics], UPSD3254 Datasheet - Page 67

• Manufacturer Part Number: UPSD3254
• Description: Flash Programmable System Devices with 8032 Microcontroller Core
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Figure 28. Serial Port Mode 0, Waveforms
Figure 29. Serial Port Mode 1, Block Diagram
SMOD
RCLK
TCLK
Overflow
Timer1
÷2
TxD (Shift Clock)
TxD (Shift Clock)
RxD (Data Out)
Write to SCON
Write to SBUF
RxD (Data In)
0
1
Receive
0
0
Send
Shift
Shift
1
1
Overflow
RI
Timer2
T
RxD
SBUF
S6P2
Clear RI
Write
to
D0
S3P1
Transition
Detector
1-to-0
D0
D1
S6P1
Sample
UPSD3254A, UPSD3254BV, UPSD3253B, UPSD3253BV
D1
÷16
Interrupt
D2
Serial
Port
Rx Detector
D2
D
CL
D3
TB8
S
Rx Clock
Tx Clock
Start
Start
SBUF
D3
Read
Q
÷16
D4
SBUF
Load
D4
D5
Zero Detector
Rx Control
Tx Control
Input Shift Register
D5
Internal Bus
Internal Bus
TI
RI
SBUF
D6
SBUF
1FFh
D6
Shift
D7
Load SBUF
D7
Send
Data
Shift
Shift
Transmit
Receive
AI06826
AI06825
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TxD